-LRB- CNN -RRB- -- The figure peers down silently from an upper floor of the ruins of a Scottish castle , wearing what looks like an outfit from the Middle Ages . Could this be a long-dead Scottish earl , or just a random , modern-day visitor ?

The mysterious image captured by Chris Aitchison at Tantallon Castle in eastern Scotland .

The eerie image is captured in a photograph taken by tourist Christopher Aitchison in May 2008 at Tantallon Castle , which sits on a rocky outcrop along the Scottish coast , east of Edinburgh . The `` person '' appears to be wearing an old-style greenish ruff around the neck .

Aitchison insists he did not tamper with the image and can not explain it .

`` I was not aware of anyone , or anything , being present in my picture , only noticing the anomaly when I got home , '' Aitchison said . `` Staff have verified that there were no sinister dummies in period costume or historical reenactments going on that day at the castle . I did not notice any nice old ladies wearing ruffs walking around the stairs ! ''

The picture was made public Friday by Richard Wiseman , a professor of psychology at the University of Hertfordshire who also studies the paranormal . Wiseman said he was looking for `` photographic evidence for ghosts '' ahead of a session on the subject at the Edinburgh International Science Festival next week . See gallery of haunted photographs ''

Wiseman solicited such photos from around the world and collated them for the conference . He said the majority of images showed mysterious-looking orbs , mists , figures and faces .

In one picture , a face appears in the side-view mirror of a parked Mercedes convertible . The photographer insists no one was around when he took the picture ; skeptics say the mirror could be reflecting the headrest or be the result of digital manipulation .

Another photo of a person walking through a creek in the woods appears to show a second person wearing a hooded sweatshirt , standing on a rock nearby . Skeptics say the `` figure '' is an illusion created by tree branches and the rock formation in the background .

Two friends raising a drink to the camera in a third photograph are joined by a ghostly third figure in the background with a face that looks like a Halloween monster mask .

`` Many of the photographs can be easily explained , '' said photographer Gordon Rutter , who also examined the pictures . `` Orbs can be caused by the camera flash reflecting off tiny dust particles , mists can result from condensed breath in front of the lens , long exposures can create ghostly figures , and apparent faces are often people seeing patterns in random shapes . ''

But the `` ghost '' in the Scottish castle has generated the most attention . What do you think about the image ?

Tantallon Castle was built in the 1350s by a nobleman and soon became the stronghold of the Douglas dynasty . For 300 years , the Douglas earls of Angus held sway at the castle as one of the most powerful families in Scotland , according to Historic Scotland , which looks after historic sites for the Scottish government .

The castle also was the scene of violence , enduring three great sieges : in 1491 , 1528 and 1651 . The last , by Oliver Cromwell 's army , resulted in such destruction that the fortress was abandoned .

It remains the `` last truly great castle '' built in Scotland , with enormously thick and high stone walls enclosing large courtyards , and high stone towers .

That stonework could explain the mysterious figure in the photograph , having caused unusual shadows . It is also possible that a member of the public was standing there when the picture was taken , Wiseman said -- in which case , he hopes they will come forward .

`` I think it 's probably a person who 's been caught in slightly odd dress , '' Wiseman told CNN . `` We know the day it was taken ... so somebody might come forward to say , ` That was me . ' ''

He added , `` If they can explain it , e-mail me . Or indeed , if they have photos they think are better , e-mail them to me . ''

A similar mystery happened five years ago at another medieval site , Hampton Court Palace , built by King Henry VIII west of London . A security camera captured a figure in period dress opening a window , peering out , then closing it again .

Palace officials insisted at the time that no one was in the room , and they were at a loss to explain the figure . It later emerged that a member of staff wearing a medieval costume was the person in the video .

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Photograph taken by Christopher Aitchison in May 2008 at Tantallon Castle

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The `` person '' appears to be wearing an old-style greenish ruff around the neck

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Aitchison insists he did not tamper with the image

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Picture made public by a psychology professor who studies the paranormal